I won, finally. My 91 lives on. Okay, here's the deal. Last fall my alternator voltage started climbing, so I replaced the regulator. No help, just added the needle wiggle at idle. Tried 2 more regulators and no hope. Replace the regulator connector and the wires to the alternator. Still no good. Replaced the alternator. Still n/g Well, driving down the road I noticed the needle pulsing and first thought Okay it's done. I wiggled the key and it came back to life, hummm It happened again, so I repeated my umm test and repeated my results. So, I bought a new ignition switch to try and it was defective, but it did prove my suspicions. Got another switch, grabbed the wrong screw and stripped the hole in the column Taped up the hole to an 8-32, put the new switch in and it bound up when I tightened the screws I loosened the screws and the bind went away so I just shimmed the switch and went on my frustrated, but merry way.
Conclusion: A voltage drop through the ignition switch could be the cause of your alternator problems.